I am trying to create xml file using XDcoument, but I am getting following error

> 
> Name cannot begin with the '<' character, hexadecimal value 0x3C
> 
> 
> 

here is my code

```
XDocument d = new XDocument(
                new XElement("<S:Envelope xmlns:S='http://schemas.xmlsoap.org/soap/envelope/'>",
                    new XElement("<S:Header xmlns:wsse='http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd'>",
                        new XElement("<ns13:ACASecurityHeader xmlns='urn:us:gov:treasury:irs:ext:aca:air:7.0' xmlns:ns10='urn:us:gov:treasury:irs:msg:acauibusinessheader' xmlns:ns11='http://www.w3.org/2000/09/xmldsig#' xmlns:ns12='http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd' xmlns:ns13='urn:us:gov:treasury:irs:msg:acasecurityheader' xmlns:ns2='urn:us:gov:treasury:irs:common' xmlns:ns3='urn:us:gov:treasury:irs:msg:form1094-1095Btransmitterupstreammessage' xmlns:ns4='urn:us:gov:treasury:irs:msg:form1094-1095Ctransmitterupstreammessage' xmlns:ns5='http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd' xmlns:ns6='urn:us:gov:treasury:irs:msg:form1094-1095BCtransmittermessage' xmlns:ns7='urn:us:gov:treasury:irs:msg:form1094-1095BCtransmitterreqmessage' xmlns:ns8='urn:us:gov:treasury:irs:msg:irsacabulkrequesttransmitter' xmlns:ns9='urn:us:gov:treasury:irs:msg:acabusinessheader'>"),
                        new XElement("Author", "Moreno, Jordao")
                        ),
                        new XElement("Book",
                        new XElement("Title", "Midieval Tools and Implements"),
                        new XElement("Author", "Gazit, Inbar")
                        )
                    ),
                new XComment("This is another comment."));

```

Can someone please help me on this? 

here is sample XML file which I want to generate using XDocument[![enter image description here](https://i.stack.imgur.com/ylu2Z.png)](https://i.stack.imgur.com/ylu2Z.png)